Hemophilia A is a disease characterized by a defect in blood clotting which results in a variety of clinical symptoms and is ultimately life-threatening. Standard treatment of the disease is administration of clotting factor VIII (fVIII), a 300 kDa plasma protein missing or deficient in Hemophilia A patients. The therapy does not cure the underlying disease, but it ameliorates the symptoms. Therefore, patients must receive repeated doses of fVIII over their lifetime. Although the administration of human fVIII to hemophilia A patients is an effective treatment, long-term therapy results in reduced efficacy for a significant proportion of the patient population. About 20-35% of hemophilia A patients develop inhibitory antibodies to human fVIII, regardless of whether the human fVIII is plasma-derived or made by recombinant technology. Patients who develop inhibitory antibodies to human fVIII experience reduced efficacy of treatment, and longer bleeding episodes. Such patients have been successfully treated with porcine fVIII, which is a substantially homologous protein. Porcine fVIII is often significantly less reactive to the anti-human fVIII antibodies found in inhibitor patients. HYATE:C, a natural porcine fVIII partially purified from pooled porcine plasma, had long been commercially available. Both human and porcine fVIII purified from plasma pose potential hazards of contamination from virus or prion particles. Such hazards are of special concern for hemophiliacs, who will receive repeated doses over a lifetime of therapy. Recombinant human fVIII, and, more recently, recombinant porcine fVIII, have been developed for their respective indications. More specifically, a recombinant porcine fVIII lacking most of the B-domain has been produced and is currently being tested for clinical application as a substitute for porcine fVIII purified from pooled porcine plasma (U.S. Pat. No. 6,458,563 incorporated herein by reference). The terms applied to these products are HYATE:C (natural porcine fVIII partially purified from pooled porcine plasma); OBI-1 (for recombinant partially B-domainless porcine fVIII). OBI-1 is also termed POL-1212 in U.S. Pat. No. 6,458,563. Both names, OBI-1 and POL 1212, refer to the same substance, porcine fVIII having the B-domain deleted except for 12 amino acids at the N-terminal part of the B-domain and 12 amino acids at the C-terminal part of the B-domain. The DNA sequence encoding OBI-1 is given in SEQ ID No:1. The deduced amino acid sequence of OBI-1 protein is given in SEQ ID NO:2, along with that of the 19 amino acid leader (signal) peptide. OBI-1 is a protein having a deduced amino acid sequence of amino acids 1-1448 of SEQ ID NO: 2. OBI-1 protein is made by expression of the DNA of SEQ ID NO:1 in a transformed mammalian host cell, which results in removal of the signal peptide, amino acids −19 to 1 of SEQ ID NO:2, and secretion of the protein from the host cell into the cell culture supernatant. Therefore, OBI-1 is herein defined as the product of expression of the DNA of SEQ ID No. 1 in a mammalian host cell. Previous studies (Doering, C. B. et al. [2002] J. Biol Chem. 277:39345-38349) have documented that the B-domain of porcine fVIII can be deleted without loss of activity.
There are several reports of various methods to provide stable fVIII in a pharmaceutical composition or formulation. Albumin has often been used to stabilize these formulations. However, because of the cost and risk associated with using albumin as a stabilizer, there are several albumin-free pharmaceutical compositions containing fVIII in the art. For example, U.S. Pat. No. 5,565,427 describes fVIII compositions which contain an amino acid or its salts and a detergent such as polysorbate or TWEEN 80, or an organic polymer such as PEG; U.S. Pat. No. 5,605,884 discloses a fVIII composition in a high ionic strength media consisting of sodium chloride, calcium chloride and histidine; U.S. Pat. Nos. 5,763,401 and 5,874,408 disclose a recombinant fVIII composition containing glycine, histidine, sucrose, sodium chloride, and calcium chloride. There are further examples of fVIII compositions having various salts, non-ionic surfactants and antioxidants (U.S. Pat. No. 5,962,650, U.S. Pat. No. 5,972,885, WO 89/09784, and WO 94/07510). WO 03/080108 describes a stable solid pharmaceutical composition devoid of amino acids which contain fVIII, a surfactant, calcium chloride, sucrose, sodium chloride, trisodium citrate, and a buffer and has a pH of 6-8 prior to lyophilization and after reconstitution in water for injection.